Rock bit



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Roca BIT Filed Feb. 18, 1938 2 Sheets-Sheet 1 .2' ihren/ar @fw C? 0272/1429 37 A' if UNITED STATES .-.earch PATENT OFFICE ROCK BIT Alfred C. Catland, Alhambra, Calif., assignor to Globe Oil Tools Company, Los Nietos, Calif., a corporation of California Application February 18, 1938, Serial No. 191,243

1 Claim.

This invention relates to a well drilling tool and relates more particularly to a rock bit for use in the rotary method of well drilling. A

general object of this invention is to provide a practical dependable rock bit embodying improved anti-friction bearing means for the roller cutters.

Another object of this invention is to provide a rock bit embodying simplified and inexpensive anti-friction bearings for the cutters.

Another object of this invention is to provide a rock bit in which a single bearing member is provided for each cutter and rows of balls cooperate with grooves in the cutters and their respective bearing members to support the cutters against both radial thrusts and a-xial thrusts in both directions. The cutter supporting bearing means of the present invention employing a single bearing member for each cutter is simple and easy to manufacture and assemble.

Another object of this invention is to provide a rock bit o1 the character mentioned in which the single 'bearing member of a cutter mounting means may directly engage against legs or wings of the bit body or against a bodypart and the bearing member of an adjacent cutter, depending upon the position of the cutter, without the necessity of employing thrust washers, spacers or other similar parts.

Another object of this invention is to provide a rock bit of the character mentioned in which the bearing members do not have transverse seams, cracks or lines of division that wear or admit particles of solid matter or that allow end play of the bearing parts.

Another object of this invention is to provide a rock bit of the character mentioned in which the single bearing members of the respective cuttersare integral except for plugs that occupy the ball admitting openings and, being integral, are simple to machine and assemble.

Another object of this invention is to provide a rock bit construction of the character mentioned embodying novel and dependable means for retaining the above-mentioned plugs in the desired position in their openings so that they cannot become displaced or cause jamming of the balls.

A further object of this invention is to provide cutter mounting means for the cutters oi a well bit in which the balls have extensive cooperation with the cutters and their bearing members, reducing the intensity of the pressures vor forces on the balls and their races and materially reducing the wear.

The various objects and features of my invention will be fully understood from the following detailed description of a typical preferred form a-nd application of my invention, throughout which description reference is made to the accompanying drawings, in which:

Fig. 1 is a side elevation of a rock bit embodying the features of the present invention with the lower portion broken away to illustrate the outer cutters and bearing means and the adjacent body parts in vertical cross section. Fig. 2 is an enla-rged top elevation of the bearing member for one of the outer cutters removed from the bit. Fig. 3 is a transverse sectional view taken as indicated |by line 3-3 on Fig. 2. Fig. 4 is an enlarged top view of one of the plugs employed in the bearing member of an outer cutter. Fig. 5 is a longitudinal sectional view of the plug shown in Fig. 4. Fig. 6 is a longitudinal sectional view of the same plug taken in aplane of sectioning at 90 to that of Fig. 5. Fig. '7 is a side elevation of the bit with the lower portion broken away to illustrate the inner cutter, their bearing means and the adjacent body parts in vertical cross section. Fig. 8 is an enlarged longitudinal sectional view of one of the large inner cutters on its bearing showing the bearing elements in elevation and Fig. 9 is a view similar to Fig. 8 showing one of the small inner cutters in cross section and arranged on its bearing.

The improved rock bit of the present invention includes, generally, a body I0, outer cutters II, bearing means I2 for rotatably mounting the outer cutters II on the body I0, sets of inner cutters I3 and I4 and bea-ring means I5 for rotatably mounting the inner cutters I3 and I4 on the body I0.

The bit rbody I0 is adapted to be connected with the lower end of a rotary well drilling string. In the particular case illustrated in the drawings a tapered screw-threaded pin I6 is provided on the upper end of the body IIJ to facilitate its connection with the drilling string. The body ID is provided with depending parts to support the cutter mounting means I2 and I5. A substantially central web I'I projects from the lower end of the body l0. The web I1 is broadened adjacent its lower end to have two downwardly and outwardly inclined wings I8. Two diametrically opposite legs I9 project downwardly and outwardly from the lower end of the body I0. The legs I9 are spaced .outwardly from the wings I8 and the inner sides 20 of the legs I9 are parallel with the opposing outer surfaces 2I of the wings I8. The inner sides 20 of the legs I9 and Room the outer surfaces 2| of the wings I8 are flat and are inclined downwardly and outwardly with respect to the vertical axis of the body I0.

The body I0 is further provided with two diametrically opposite legs 22 projecting from its lower end. The legs 22 are spaced substantially from the legs I9 and their lower portions are substantially vertical, The web I 1 with its wings I8 and the legs I9 and 22 are preferably integral parts of the body IIJ. It is to be understood that the body I0 is provided with the usual circulation passages and discharge ports for the circulation fluid employed in the rotary method of well drilling.

The outer cutters I| are provided to act on the outer portion of the bottom wall of the well and to cut the well bore to gauge. The cutters II are in the nature of toothed roller cutters and there are two cutters II, one being mounted between each set or pair of adjacent wings and legs I8 and I9. The outer cutters II are frustoconical, having pitched or inclined peripheries and flat opposite ends. A centra-l longitudinal opening 23 extends through each cutter II. The peripheries of the cutters II are provided with suitable cutting teeth 24. The ends or corners of the teeth 24 at the large ends of the frusto-conical cutters I I are cut away or bevelled off at 25 to act on the side wall of the well bore as will be subsequently described.

In accordance with the invention annular ball races or grooves are provided in the interior of each cutter II. In the preferred construction illustrated in the drawings two axially spaced annular grooves 26 and 21 are provided in the wall of each cutter opening 23. The grooves 21 are provided in the base end portions or the large end portions of the frusto-conical cutters and may be somewhat larger in diameter than the grooves 26. An annular recess or socket 28 is preferably provided in the outer or large end of each cutter in concentric relation with its opening 23.

The bearing means I2 for rotatably supporting the outer cutters II are in the nature of antifriction ball bearings. As the two bearing means I2 may be identical, I will proceed with a detailed description of one bearing means I2, it being understood that such description is equally applicable to the other bearing means I2.

'The bearing means I2 includes a race or bearing member 29. The bearing member 29 is a generally cylindrical spool-like member adapted to be received in the opening 23 of a cutter I I. The member 29 is provided with a central longitudinal opening 30 extending through it from one end to the other. The opposite ends of the bearing member 29 are at and are adapted to cooperate with the opposing surfaces 20 and 2| of the adjacent body leg I9 and wing I8. An annular radial flange 3| is provided at the outer end of the bearing member 29 and is partially received in the socket 28 of the cutter I I to assist in preventing the entrance of cuttings and particles of solid matter to the cutter opening 23. The periphery of the bearing member 29 is provided with two spaced annular ball grooves 32 and 33. The groove 32 directly opposes the groove 26, while the groove 33 directly opposes the groove 21, The sets or pairs of grooves 26 and 32 and 21 and 33 are of substantial depth, as illustrated throughout the drawings.

The bearing means I2 further includes balls 34 occupying or cooperating with the pairs of opposing or registering grooves 26 and 32 and 21 and 33. The balls 34 rotatably support the cutter II on the bearing member I2 with a minimum of friction. Because of the substantial depths of the grooves 26 and 32 and 21 and 33 the balls 34 are operable to assume the end thrusts in both directions as well as the radial thrusts and therefore may constitute the sole means for rotatably supporting the cutters |I. Accordingly,

the ends of the cutters need not bear on thrust washers or thrust surfaces of the body I0. The sets or pairs of opposing grooves 26 and 32 and 21 and 33 are related so that the balls 34 have extensive cooperation with the grooves for the transmission of axial thrusts both inwardly and outwardly with respect to the central vertical axis of the bit.

The bearing member 29 is provided with a radial opening 35 extending from the bottom or wall of the groove 32 to the opening 30 and a similar radial opening 36 extending inwardly from the bottom or wall of the groove 33 to the opening 30. The openings 35 and 36 may be simple cylindrical bores and are sufficiently large in diameter to receive or pass the balls 34. The openings 35 and 36 provide for the easy insertion or arrangement of the balls 34 in the pairs of opposing grooves 26 and 32 and 21 and 33, respectively. Following the arrangement of the bearing member 29 in the opening 23 of the cutter II the balls 34 are passed outwardly through the openings 35 and 36 to the opposing grooves 26 and 32 and 21 and 33 to occupy the same and thus rotatably support the cutters on the bearing member.

The invention provides simple and dependable means for retaining the balls 34 in the pairs of opposing grooves 26 and 32 and 21 and 33. This means includes a plug 31 for occupying the opening 35 and a similar plug 38 for occupying the opening 36. The plugs 31 and 38 are arranged in their respective openings 35 and 36 following the arrangement of the balls 34 in the opposing grooves as just described and their outer ends are shaped to constitute ush continuations or portions of the walls of the grooves 32 and 33, respectively. A transverse groove or notch 39 is provided in the outer end of the plug 31 and a similar groove or notch 4D is provided in the outer end of the plug 38. The notches 39 and 40 are formed so that their walls constitute flush continuations of the grooves 32 and 33, respectively. The openings 35 and 36 are preferably in the upper part of the bearing member 29 so that the plugs 31 and 38 are not subjected to the heavy forces transmitted between the cutter I and the member.

The invention provides dependable means for holding the plugs 31 and 38 against outward movement and against turning so that the walls of their notches 39 and 40 remain in ush relation with the walls of the grooves 32 and 33. This means includes a groove or keyway 4| in the wall of the opening 30 and ears or keys 42 and 43 on the plugs 31 and 38, respectively, for cooperating with the keyway 4|. The keyway 4| may extend between the opposite ends of the opening 30 and intersects the openings 35 and 36. The keys 42 and 43 are in the nature of lugs or ears projecting radially from diametrically opposite sides of the plugs 31 and 38, respectively. The keyway 4I may be flat-walled or rectangular in cross section and the keys 42 and 43 may be correspondingly shaped to t the keyway. The keys 42 and 43 are preferably integral with their respective plugs 31 and 38 as illustrated in the drawings, although it is obvious that they may be separately formed parts suitably fixed to the plugs if desired. It is believed that it will be apparent how the cooperation of the keys 42 and 43 with the keyway 4I holds the plugs 31 and 38 against turning and against outward movement so that the notches 39 and 48 remain in flush relation with the walls of the grooves 32 and 33 respectively.

Following the assembly of the bearing member 29 in the cutter opening 23, the arrangement of the balls 34 in the sets of registering grooves 26 and 32 and 21 and 33 and the placing of the plugs 31 and 38 in their respective openings 35 and 36, the assembly of the cutters II and their bearing elements is inserted between a leg I9 and a wing I8. As described above the outer end of the bearing member 29 may engage the inner side 28 of the leg I9 and the inner end of the bearing member may engage the surface 2l of the wing I8. It is preferred to provide a lug 45 on the outer end of the bearing member 29 to engage upwardly against the lower end of the leg I9 for the direct transmission of forces between the bearing member and the body leg. A similar lug 46 is provided on the inner end of the bearing member 29 to engage upwardly against the lower end of the Wing I8 for the direct transmission of forces between the bearing member and the body wing. It may be desired to weld the lug 45 to the leg I9 at 41 to assist in securing the bearing member 29 to the body.

'I'he means I2 for mounting the outer cutters II further includes a supporting member or pin 48. A downwardly and inwardly inclined opening 49 is provided in the wing I8 and a downwardly and inwardly inclined opening 58 is provided in the leg I9 to be in axial alignment with the opening 49. The opening 38 in the bearing member 29 is in registration with the openings 49 and 58 when the assembly of the cutter II and its bearing elements is in place between the wing I8 and the leg I9. The supporting pin 48 is passed outwardly through the opening 49 and the opening 30 and has its outer end portion threaded in the opening 58. A head 5I on the inner end of the pin 48 cooperates with the wing I8. The head 5I may be counter-sunk or recessed in the inner side of the wing I8. 'I'he outer part of the pin 48 may be distorted or peened over at 52 to lock the pin against unthreading. The pin 48 cooperates with the plugs 31 and 38 to hold the plugs against inward movement. The pin 48 may be tightened down so that the ends of the bearing member 29 are tightly held between the inner side 28 of the leg I9 and the surface 2| of the wing I8 so that there is no end play or movement in the bearing member and the cutter assembly,

The outer cutters I I rotatably supported on the body I8 as described above, are rotatable about downwardly and inwardly inclined axes and project downwardly beyond the lower ends of the wings I8 and the legs I9 to act on the bottom wall of the well bore and project outwardly beyond the legs I9 so that the bevelled-off corners 25 of their teeth 24 may act on the side wall of the bore. It will be understood how the outer cutters II make an annular cut in the earth formation to cut the well bore to gauge.

The inner cutters I3 and I4 are provided in sets, there being two sets of inner cutters each including a cutter I3 and a cutter I4. 'I'he cutters I3 are arranged at the inner sides of the legs 22 to act within and in-overlapping relation to the path oi' travel of the cutters II and the cutters I4 are located at the opposite sides of the web I1 to act on the inner or central portion of the well bore. The cutters I3 and I4 are roller cutters, the cutter I3 being frusto-conical and the cutters I4 being cylindrical. Suitable cutting teeth 53 are provided on the inclined or pitched peripheries of the cutters I3 and suitable teeth 54 are provided on the peripheries of the cutters I4. The frusto-conical cutters I3 are arranged so that their small ends are larger in diameter than the cylindrical cutters I4.

Central longitudinal openings 55 extend through the cutters I3 and concentric recesses or sockets 56 are provided in the large ends of the cutters I3. Spaced annular ball grooves 51 and 58 are provided in the walls of the cutter openings 55. The grooves 51 and 58 are of substantial depth and the grooves 58 in the outer end portions of the cutters face axially outward as well as inwardly toward the central longitudinal axes of the cutters. The cutters I4 are provided with central longitudinal openings 59. There are two spaced annular ball grooves 68 and 6I in the wall of each cutter opening 59. In the preferred construction the body web I1 is provided adjacent its lower end with cylindrical bosses 62 projecting outwardly toward the legs 22. The openings 59 in the cutters I4 are proportioned to receive the bosses 62 with suitable clearance.

The bearing means I5 for rotatably mounting the inner cutters on the body I8 comprises a single bearing member 63 for each cutter I3, a single bearing member 64 for each cutter I4 and a single support member 65 carried by the body web I1 and the legs 22 and supporting the members 63 and 64.

'Ihe bearing members 63 for the cutters I3 are generally cylindrical spool-like parts having central longitudinal openings 66. The outer ends of the members 63 are adapted to cooperate with the inner sides of the body legs 22 and the inner ends of the members 63 are engaged by the members 64 as will be subsequently described. Annular radial anges 61 are provided on the members 63 at their outer ends and are received in the sockets 56 with suitable clearance. The members 63 are received in the openings 55 of the cutters I3 with clearance and the flanges 61 received in the sockets 56 serve to prevent the entrance of large particles of solid matter to the openings. Each member 63 has two longitudinally spaced ball grooves 68 and 69. The grooves 68 oppose or register with the grooves 51 and the grooves 69 oppose or register with the grooves 58. In the preferred construction a lug 18 is provided on the outer end of each member 63 and cooperates with the lower end of a body leg 22 to prevent rotation of the member and to transmit forces between the body leg 22 and the bearing member.

The bearing means or cutter mounting means I5 further includes series of balls 1I occupying or cooperating with the sets of registering grooves 51 and 68 and 58 and 69. The balls 1I rotatably support the cutters I3 on the bearing members 63 for free rotation. The grooves 51 and 68 and 58 and 69 are proportioned and related to substantially entirely receive the balls 1I so that the balls are operable to transmit axial thrusts in both directions as well as the radial thrusts and thereby constitute the sole means for rotatably supporting the cutters I3. 'Ihe grooves 58 and 69 are faced and related so that the balls 1I cooperating with them dependably transmit the outward end thrusts imposed on the cutters I3. The cutters I3 being supported entirely by the balls 1| do not bear on the members 63 and need not bear on the flanges 61 or the body legs 22.

The members 63 are provided with radial openings 12 extending outwardly from their openings 66 to the grooves 68 and have similar openings 13 extending outwardly from their openings 66 to the grooves 69. The openings 12 and 13 are proportioned to admit the balls 1I and facilitate the arrangement of the balls in the sets of registering grooves 51 and 68 and 58 and 69. Following the insertion of the balls 1| in the sets of grooves a plug 14 is arranged in each opening 12 and a similar plug 15 is arranged in each opening 13. The outer ends of the plugs 14 and 15 are shaped or notched to form flush continuations of the walls of the grooves 68 and 69.

Means is provided for holding the plugs 14 and 15 against outward movement and against turning. A longitudinal keyway 16 is provided in the wall of each opening 66 and the plugs 14 and 15 have lugs or keys 11 cooperating with the keyway 16. The keys 11 cooperate with the keyway 16 to hold the plugs against turning and to prevent outward movement or displacement of the plugs so that the upper ends of the plugs remain flush with the Walls of the grooves 68 and 69. It is preferred to relate the openings 12 and 13 with the lug 16 so that the openings are in the upper portions of the members 63 when the lugs are engaged against the lower ends of the body legs 22. With this relation of partsl the plugs 14 and 15 and the adjacent Walls of the grooves 68 and 69 are not subjected to the heavy forces transmitted between the cutters I3 and the members 63. The lugs 10 cooperate with the legs 22 for the transmission of forces between the body and the bearing members 63 and if desired may be welded to the legs as illustrated in the drawings.

The bearing members 64 are cylindrical tubular members having central longitudinal openings 18. The members 64 are proportioned to t the cutter openings 59 with suitable clearance. The outer ends of the members 64 engage against the inner ends of the members 63 and the inner ends of the members 64 cooperate with the end faces of the bosses 62. Each bearing member 64 is provided with an annular ball groove 19 adjacent its outer end and a peripheral annular ball groove 80 at or adjacent its inner end. The members 64 are preferably reduced in external diameter at their inner ends so that their peripheral surfaces join with the bottoms of the grooves 88 as illustrated in Figs. 7 and 9 of the drawings. The grooves 19 oppose or register with the grooves 6| and the grooves 80 oppose or register with the grooves 60. Series of balls 8| occupy or cooperate with the sets of opposing grooves 6I and 19 and 50 and 8|). The grooves just mentioned are proportioned so that the balls 8| are effective in supporting the cutters I4 for free rotation and so that the balls constitute the sole cutter supporting elements. The balls 8| in the grooves 6| and 19 are operable to transmit end thrusts in both directions as well as the radial thrusts while the balls 8| in the grooves 60 and 80 are operable to transmit the outward end thrusts as well as the radial thrusts.

In assembling a bearing member 64 in a cutter I4 a row of balls 8| is rst arranged in the groove 60 and the member 64 is inserted in the cutter opening 59 and moved to a position where its radial opening 82 is provided in each member 64 and extends from its opening 18 to its groove 19. The openings 82 are provided to admit the balls 8| to the registeringl grooves 19 and 6I. Following the insertion of the balls 8| in these grooves plugs 83 are arranged in the openings 82. The outer ends of the plugs 83 are shaped or notched to form ush continuations of the surfaces of the grooves 19. The plugs 83 are inserted from the inner ends of the openings 82 and means is provided for holding the plugs against turning and outward movement. Keys 84 are provided on the plugs 83 and cooperate with keyways 85 in the walls of the openings 18. The keys 84 cooperating with the keyways 85 serve to retain the plugs 83 in the positions where their outer ends form ush continuations of the walls of the grooves 19.

The supporting member 65 serves to mount or support the bearing members 63 and 64 on the body I0. The web I1 is provided with a transverse or horizontal opening 86. The opening 86 is concentric with and extends through the bosses 62. The lower portions of the legs 22 are provided with openings 81 in longitudinal alignment with the opening 86. The pin or supporting member 65 is passed through the opening 81 in one leg 22, has its intermediate portion. supported in the opening 86 and has an end portion threaded in the opening 81 in the other leg 22. The opposite end of the supporting member 65 is provided with a head 88 recessed in the outer side of the adjacent body leg 22. The member 65 extends through the openings 66 and 18 of the members 63 and 64, respectively, to support the members and their respective cutters I3 and I4. The member 65 may engage or cooperate with the inner ends of the several plugs 14, and 83 to positively prevent inward movement or displacement of the plugs and to retain their respective keys 11 and 84 in cooperation with the keyways 18 and 85. The support member 65 may be threaded or tightened so that the pairs of bearing members 63 and 64 are clamped together between a body leg 22 and a boss 62 so that there can be no end play in the bearing elements or members.

The inner cutters I3 and I4 rotatably mounted on the body Ill as just described are independently rotatable about a common transverse axis. The cutters I3 project downwardly beyond the lower ends of the legs 22 to act on the bottom wall of the well and the cutters I4 project downwardly beyond the lower end of the web I1 to act on the central portion of the well bottom.

It is beieved that the operation of the improved rock bit will be understood from the foregoing detailed description. The body I0 is adapted to be secured to the lower end of a drilling string which is to be rotated in the Well b-ore and fed downwardly in the usual manner. The cutters individually rotate and are supported by the anti-friction ball bearing means to rotate with a minimum of friction. It is to be observed that the outer cutters I! are each rotatably supported by a single integral bearing member 29. The bearing members 29 are securely held between the body wings I8 and the legs I9. As the members 29 are one-piece and devoid of joints and lines of division there can be no play or working of the parts. Each inner cutter I3 is rotatably supported on a single bearing member 63 through spaced series of balls 1I. The members 63 are securely held betwen the legs 22 and the bearing members 64`and cannot work or play. The cutters I4 are supported on the simple integral bearing members 64 through the medium of the balls 8l. The members 64 are securely clamped between the members 63 and the bosses 62.

It is to be particularly noted that the bearing members 29, 63 and 64 are simple and inexpensive t'o manufacture and to assemble. The several cutters are supported solely by spaced series of balls and it is unnecessary to employ thrust Washers or similar parts that are subject to excessive Wear. There is a minimum number of parts embodied in the bearing means and the parts are all securely held in place so that they cannot become lost.

Having described only a typical preferred form and application of the invention, I do not wish to be limited or restricted to the specific details herein set forth, but wish to reserve to myself any variations or modifications that may appear to those skilled in the art or fall within the scope of the following claim.

Having described my invention, I claim:

In combination, spaced supports, a boss on one support projecting toward the other, a roller having an opening, a pin extending between the supports and passing through the opening, a tubular bearing member on the pin having two spaced peripheral grooves, one spaced from one end of the member, the other adjacent the other end of the member, the member being reduced in external diameter from its said other end to the said other groove, the member having a radial opening joining the first mentioned groove, balls passed through the radial opening into the said rst mentioned groove to rotatably support the roller, balls passed over said other end of the member into the said other groove rotatably supporting the roller, a plug in the radial opening, means holding the plug against movement, and means holding the member where its said other end engages the boss and the boss is received in the roller opening.

ALFRED C. CATLAND. 

